<template>
  <div class="container">
    <div class="item1"></div>
    <div class="item2"></div>
    <div class="item3"></div>
  </div>
</template>

<script>
export default {
  data() {
    return {};
  },
  methods: {},
};
</script>

<style scoped>
.container {
  display: flex;
}
.item1 {
  flex-grow: 1;
  height: 100px;
  background: red;
}
.item2 {
  flex-grow: 2;
  height: 100px;
  background: blue;
}
.item3 {
  flex-grow: 3;
  height: 100px;
  background: green;
}
</style>